How's it going? I found you guys in a google search. I know a little about computers, but not enough. If you guys could help me, I would greatly appreciate it. I received the BSOD.

The computer is a

Dell (go figure, Ive kept it running well for about 6 years now)
Windows XP
2 GB RAM
GeForce 6500

Anyway, the error message is:

DRIVER_IRQL_NOT_LESS_OR_EQUAL

Tech info:

STOP: 0x000000D1 (0x00A427E4, 0x00000002, 0x00000000, 0xBAD64CD9)
RT2500.sys - Address BAD64CD9 base at BAD4E000, DateStamp 42675c99

My computer keeps restarting and it wont boot up in safe mode.

0xD1 are usually caused by faulty drivers. The driver cited in your information as the cause is RT2500.sys which belongs to your wireless adaptor/NIC card.

Go to Dell's website, find your model, and update the latest drivers for your system.

Why would this error just be happening now?

That is a good question that really doesn't have a specific answer. For example, people will be able to play the same game, with the same video card and drivers and for some unknown reason the drivers begin to cause issues. Many times there is no rhyme or reason, but either an update to a new driver(s) or a complete uninstall/reinstall is needed and all is good.

It also could be pointing to the fact that your hardware may be going. But right now all we can go with is what the dump analysis shows.