Would Hardware Upgrades Solve These Problems?

This doesn't sound right; which version of Windows are you using?

XP Pro

I have a Dell Vostro 420 purchased in July 2009, with these components: CPU: Core 2 Duo E8400/3.0GHz 6M 1333FSB HDD: 250GB Serial ATA Hard Drive 7200RPM, 8MB Cache RAM: 4GB Non-ECC 800MHz DDR2 4X1GB VIDEO: 256MB ATI Radeon HD 3450 1st PROBLEM -------------------- I work online researching various subjects, usually ending up with a lot of tabs open in IE8. After about 10 or 12 open tabs, my PC bogs down, gets very sluggish, screens freeze, and my hard drive starts to emit a high pitched humming sound.   I can fix this by opening Windows Task Manager and using End Process to close out all the instances of iexplore.exe.   After I do that, the PC runs normally again. 2nd PROBLEM --------------------- Videos often pause while the loading symbol spins, and "grabbing" a large graphic to move it around the screen is often a very sluggish process. QUESTION ----------------- Are there any hardware upgrades I can make so my PC can handle the load; for example, a new hard drive, additional memory, new video card, etc.? I only afford to upgrade, don't have the funds to buy a newer PC. Thanks for your suggestions!

Windows XP generally has decreased performance the longer it is used that is quite normal. You can try to clean out the temporary files using CCleaner.

I would recommend a clean installation of Windows although optimally you should upgrade to Windows 7  bit. However an upgrade to Windows 8 (preferably the 64 bit version) should be more econmic so long as you buy before January 2013 when the promotional offer expires. See my wiki Win Idows Reinstallation Guide for any of these scenarios: http://en.community.dell.com/support-forums/software-os/f/3524/t/19480753.aspx If going for Windows  also recommend installation of Start8 http://www.stardock.com/products/start8/ as Windows 8 interface isn't great on its own on a Desktop. Microsoft will terminate all support for WIndows XP in just over a year so you should really upgrade to anewer version of Windows sometime soon.

Looking at the Dell FTP Website. The nVidia NV GT220(1G DDR3) card was sold with this model which should help with your Graphics problem.

You can purchase this card from Amazon here: http://www.amazon.com/EVGA-GeForce-Express-Graphics-01G-P3-1226-LR/dp/B002SG7LUQ/ref=sr_1_2?ie=UTF8&qid=1356658811&sr=8-2&keywords=nVidia+NV+GT220 

You can also get this card here from Dell Parts and Upgrades the GT630 which should be better and is listed compatible for this model: http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&s=dhs&cs=19&sku=A6116822&mfgpid=199729&chassisid=8580

Other upgrades you can put in the system to speed it up is a Solid State Drive and more memory from crucial: http://www.crucial.com/upgrade/Dell-memory/Vostro+Desktops/Vostro+420+Tower-upgrades.html If you are installing 8 GB of RAM ensure that you have the 64 bit version of Windows 8. The graphics card is probably what you want the most but I would highly recommend upgrading to Windows 8 and Start8 before the promotional discount expires.

Well Windows 7 professional is better than XP Professional which is what you said you have just now. I only recommended Windows 8 because it was cheaper.

I gave you some recommendations for the Video Cards.

However see here: <ADMIN NOTE: Broken link has been removed from this post by Dell>

http://support.dell.com/support/edocs/systems/vos220/en/sqrg/sqrg_en.pdf

You should use a PCIe-x16 graphics card probably low profile if you want a quiet one.

The Sapphire 6450 is silent, yet much faster than the old 3450. An SSD for your OS drive would bring another big boost to performance.

As for Windows, Windows 7 may well be slated to become the "new XP" in that many users will cling to it as long as possible, but the Professional version is $120 on sale, versus $40 for Windows 8. In fact, I bought a copy of Windows 8 and have yet to install it.

My error: win7 pro on my Vostro 420, xp pro on my laptop.,

My error: win7 pro on my Vostro 420, xp pro on my laptop.,

Okay in that case, run CCleaner on the Desktop, Both the Cleaner and Registry Cleaner (and back up the registry). Also run defraggler.

Assuming Windows 7 Professional 64 bit.

The upgrades I suggest most in order are the graphics card, the solid state drive (requires a clean install of Windows for maximal performance) and the memory.