Blue screen error/ previous computer issues (with details)

Windows XP Home SP3
Intel Core2 Duo E6550 @2.33GHz
2.0GB RAM
ATI Radeon HD 2600 XT

I've had a good share of problems with my computer since I bought it; most have been related to the PC freezing and automatically restarting or to blue screen errors. Some of these problems could be related, but I don't think any of them are due to spyware, malware, virus etc. I've already run fulls scans on Malwarebytes' Anti-Malware, SUPERAntiSpyware and Avast without any issues.

Dec, 2007: Blue screen error
page_fault_in_nonpaged_area
0x00000050

Not sure what caused the error or if it was ever fixed. Dell support said it could be do to new software, spyware, malware, virus etc.

Aug, 2008: Blue screen error
driver_irql_not_less_or_equal
0x000000D1

Same response from Dell.

May, 2009: Found new hardware

I started getting a "found new hardware" message on start-up without having installed anything new. There was an unknown device in the device manager related to "logmein" (remote access software). I had already uninstalled Logmein, so this was probably just some leftover file. I went ahead and uninstalled the device as well and it solved this issue. I don't think this is related to any of the other problems, but it's worth mentioning.

Nov, 2009: Checking file system on C:
"the type of the file system is NTFS"
"the volume is dirty"

I got this message on start-up once or twice in addition to the PC freezing and automatically restarting several times. I got some help from another forum and the problem was thought to be caused by a failing hard drive. I ran the hard drive diagnostic tool on Ultimate Boot CD without any errors.

Yesterday: Blue screen error
page_fault_in_nonpaged_area
ati3duag.dll

I got this message yesterday after exiting Civilization IV. I forgot to make a note of the stop code. The file "ati3duag.dll" makes me think that the error is related to my video card. The first blue screen error I got in 2007 also had "page_fault_in_nonpaged_area". Could they be related? Also, I was looking in my device manager and under display adapters is "logmein mirror driver". I'm assuming this is just another leftover file. Is it safe for me to uninstall this?

Thank you in advance to anyone who can help.