Dell Dimension 3000 crashes

Okay, I have an old dinosaur of a computer in a Dell Dimension 3000 that I got back in 2005.  Starting several months ago, I would get little blurry regions on my monitor or a barely visible black line.  The blurry areas would kind of shimmer.  If I wiggled my VGA cable a bit, these areas would either move to a new area or disappear altogether.  This went on for some time and I wasn't overly concerned.

About a month ago I was watching a video when all of a sudden my PC crashed and I was staring at a frozen image of garbled colors.  I held in the power button to restart and was fine for two days until when I tried to boot up my PC,  my monitor said that there was no signal coming from the computer before it went into standby mode (the light on the monitor turned yellow).

I tried all sorts of things to get it running again by searching around online.  I removed my RAM sticks to clean them before reinserting them. removed dust, etc.  A few of the capacitors were bent on the motherboard and I seemed to be able to fix things by bending them back in place.  None of them had blown their caps, but some of their silver tops had a blueish tint to them.

I got by the crashes and no signal detected through doing this for a couple weeks.  A couple days would pass without issues but then they would reappear.  It seemed to get a little bit harder over time.  Yesterday was an issue.  All my usual tricks weren't working for a while.  I got it running again but after I had noticed a few things... the green grounded light on my power strip was lit up and I thought to myself... I don't overly recall seeing it on lately.  Also, the fan on my power supply was no longer running.

Where I stand right now is that I'm using a personal desk fan of mine to blow cold air on the power supply and see if that fixes it.  I didn't crash again yesterday after I began using the fan but I did this morning just right as Skype had loaded up.

I should also note that about a month before the crashing started I had removed an excessive amount of dust from the inside of my PC.  I had neglected cleaning it for a while, but what triggered me to do it was by how loud my PC was and I detected a burnt smell.  No parts of the motherboard look blackened or cooked.  Unfortunately I had forgotten to clean out the power supply until yesterday, so I don't even know how long it has been out.

Should I invest in a new PSU or is my PC pretty much too far gone?  I fear I might have done damage by not removing the dust sooner or by my ungrounded power strip... or a combination of the two.  I never got any motherboard beeps, blue screens, or random reboots, however.

Sorry if my post seems like I'm rambling... I'm just really tired and frustrated and want to keep this old fossil going until I have the money to buy a new PC.