Time for a new PC, or at least a cheap mechanical hard drive:
http://www.pccasegear.com/index.php?...ducts_id=15934
Then reload XP. That CPU isn't too bad, and 1.5gb is enough. We still run heaps of these old P4 IBM machines with around 512-1.5GB ram at work, but the hard drives are starting to go on some.
So say you get a new disc drive, it might last another year- then the power supply will die, they have rated hours and at 7+ years of high use you are getting close to the end.
So then you spend another 40 on a power supply and still have a slow PC.
But if you don't want to spend heaps of money on a new PC but want something newer/faster/more reliable, just have a look on ebay:
http://www.ebay.com.au/itm/Dell-Opti...ht_3214wt_1139
OR actually this too:
http://www.ebay.com.au/itm/Dell-755-...item2eb9f98fea
I know it doesn't directly solve your problems, but it does still solve your problems, if you know what I mean