Photoshop Lag

Hi...I've been using photoshop (Photoshop 6.0) mainly for fun, dealing with picture editing and drawing for flash movies and stuff. Anyways, just recently, my photoshop started lagging...badly. For example, it takes way longer to load at startup, and using all the tools lags really badly. Everything just goes slow. Along with the tools, when I'm looking at another window, and go back to photoshop, it'll freeze for a little. Basically, the program has slowed down a LOT.

I think (but I'm not sure) that it has to do with me resizing some pictures for my mom recently. She's an artist, and had her pictures taken at a studio and saved onto 2 discs, which she gave to me to resize and print as thumbnails. I'm sure you guys know that pictures taken by a digital camera at a studio are HUGE, so loading/opening the pictures takes some time, as does the resizing. I'd say I had to resize about 30 pictures, which took quite some time. I believe that it was after this little project that it began to lag pretty bad.

Has this happened to anyone else, and do you guys know how to fix it? If I have to re-install, will I lose all my .psd files? Thanks a lot for your help.

Anyone?

run defragment on your local drives,
increase vitrual memory,
run scan disk,
clean up old compresed files, (right click on c:\ in my computer folder go to disk cleanup select all and hit ok)
clean up all the temp files,
temp internet files, cookies,

that usualy works for me to this procces at least once a month, it works for me...