KVM switch/other solution for laptop, PC and dual monitors

There are several.  But dual display KVMs are somewhat rarer, and the cost varies significantly based on the type of display outputs you need and especially the resolution of the displays you want to use.  And since I doubt your 5290 and XPS PC have any display output connectors in common, you'll probably need some adapters to connect one or both of them to the input sides of the KVM.  If you can post the display model(s) you intend to use and the exact model of your XPS PC (or at the very least the types of display ouptuts that it has), then I may be able to find a specific KVM that would work as well as recommend any suitable adapters.

MonitorLatitude connectors #1Latitude connectors #2Monitor connectorsXPS Connectors

I've attached photos of all connectors for your reference.  I am very appreciative of your assistance!

Unfortunately image attachments are initially only visible to Dell reps and the person who uploaded them, until they get "approved" by Dell reps.  Can you just post the model names of your displays and your XPS desktop?

Made some edits to my above post since I noticed that one of the outputs on the KVM was HDMI rather than DisplayPort.  Will still work, just had to change a note about cabling.

Ok, the images showed up.  First off, looking at dual display KVM models, there are options for VGA, DVI, and DisplayPort.  VGA looks noticeably worse than any other option since it's the only analog signal format (although it looks like that's what you're using at the moment....) and DVI is obsolete, so DisplayPort would normally be the way to go.  There are also a few HDMI KVMs, but they're actually quite a bit more expensive than the already-expensive DisplayPort options, and HDMI is actually a worse solution than DisplayPort anyway.  One of the conveniences unique to DisplayPort is that it supports "MST", which is multi-stream transport.  That allows it to drive multiple independent displays from a single cable, which makes things easier when connecting the systems to the KVM.

The problem with DisplayPort in your case is that the video card in your older XPS desktop doesn't have a DisplayPort output, and you can't use an adapter to convert a DVI or HDMI signal into DisplayPort, only the other way around.  I see a DisplayPort output built into the system itself just to the left of that graphics card, but that output would be driven from built-in Intel GPU rather than whatever discrete GPU you have.  If this is an old system and you're not concerned about graphics performance, you could potentially switch over to that output and physically remove the discrete graphics card, but even then I don't know if the built-in GPU supports DisplayPort 1.2, which is required for MST.  Again, if you provided the actual model of that system, I might be able to find out.  If the built-in DisplayPort output doesn't support DP 1.2 and/or you don't want to fall back to using the Intel GPU, honestly your best option would be to upgrade the graphics card in that system to any GPU that has a DisplayPort 1.2 or newer output (DisplayPort is up to 1.4).  If you're not worried about graphics performance, you can probably find a suitable GPU for about $40-50.

Once you get DisplayPort 1.2 from your desktop, then all you'd need in order to get it out of your Latitude is a USB-C to DisplayPort cable like this one.  Then you'd use this KVM.  It supports 2 source systems and offers an HDMI output and an MST-capable DisplayPort output.  The latter would allow you to drive multiple external displays off a single cable from that one output if the displays supported MST themselves, but your display doesn't -- but that's ok, read on.  The KVM also offers USB 3.0 ports, although for the latter you'll of course only want to connect USB devices that you want to switch between active PCs, i.e. don't connect an external hard drive that should always stay attached to one PC.  Again, there's only one DisplayPort input per source PC here because the input signals for both of your external displays will be coming over a single cable from each PC.  I do this with my Latitude 7480 and dual Dell U2717D displays and it works perfectly.

So to set it up, you'd do this:
- Use the included DisplayPort cable to connect the XPS to the KVM, and the USB-C to DisplayPort cable to connect the Latitude to the KVM.
- Use the included USB 3.0 cables to connect a USB port from each source system to the KVM.
- Connect your keyboard, mouse, and any other USB devices you want to use in "switched" mode to the USB ports on the KVM.
- Connect your displays to the KVM.  Use one of the included DisplayPort cables for one, and then use a regular HDMI cable for the other.  DisplayPort and HDMI will perform identically to each other on your displays.

PC system is XPS 8700, Service Tag 

Ok, that system shipped with the Intel i7-4790 CPU, which includes the HD Graphics 4600 GPU.  I have that same GPU in my XPS 15 9530 laptop and I'm able to use DisplayPort MST just fine, so I would expect that would be the same in your case.  But you might find that you have to physically remove your existing discrete graphics card before the other outputs built into your system will work -- or you might find that they work now, I'm not sure.  Anyhow, the solution I described above will give you the KVM setup you want, but here are two other options in case you're curious.  One of them is less expensive and somewhat less convenient, and the other is more convenient and more expensive:

Less expensive, less convenient: You can skip the KVM entirely in favor of having both systems cabled to both displays and then toggling the inputs on each display back and forth when you want to switch PCs.  On the Latitude, you'd use a USB-C to DisplayPort cable for one display and a VGA cable for the other -- and for the desktop you'd use an HDMI cable for one display and a DVI-to-HDMI cable for the other.  The downside of course is more cables and your Latitude would have to use VGA for one display, which isn't ideal for quality.  But for USB switching in this setup, you could use a small USB hub for your keyboard and mouse and then physically move that USB hub's cable between PCs to switch back and forth.  I do something like this with two laptops on my desk, although it's a bit easier for me because my displays have a DisplayPort output, so I have Display #1 directly connected to Display #2.  This means I only have one display cable coming out of each PC, and I can change the input only on Display #2 to switch both displays over to the desired PC.  This still wouldn't get you audio switching between systems, though.  If you wanted that, you'd also have to move your speaker cable around, which would probably be inconvenient if you have a desktop and laptop.

More expensive, more convenient: With the KVM setup I originally described in my earlier post, your laptop will still need to have a display cable, audio cable, power cable, and at least one USB cable all plugged into it.  That can obviously become inconvenient if you take your laptop with you frequently.  You can solve that by adding a dock to this solution, such as the Dell WD15.  In this scenario, you'd connect one set of the KVM input cables to the dock, and then connect the dock to your XPS 13 via the dock's USB-C cable.  The end result in terms of the the KVM functionality will be the same, but the added advantage to this setup is that the single USB-C cable coming from the WD15 dock to the XPS 13 will carry power, video, USB, and audio, which makes it much easier to connect and disconnect your laptop at your desk.  But of course this involves purchasing a dock in addition to the KVM.  Also note that the WD15 dock uses a Mini-DisplayPort output, so if you wanted to go this route, instead of buying a USB-C to DisplayPort cable to connect the XPS 13 straight to the dock, you'd instead need a Mini-DisplayPort to DisplayPort cable to connect the dock to the KVM.

Thank you so much.  I will do as you suggest.