Do you perform regular computer maintenance, such as emptying temporary internet files, temp files, recycle bin, histories etc... Temporary files can fill your harddrive up quit quickly and the existance of cookies and old download files can cause the slowdown of a computer.
Do you also do regular disk defragmetation to reorder the file locations on your hard-drive. 1 year is a pretty standard time for a new system to slow down if never maintenanced. When you move or delete a file on your hard-drive it is still actually located on the orginal harddrive byte/s and therefore duplicated over and over everytime you move, change or delete a file, so defrag is a must.
Check the temp of your processor and that your fans are all running. If your CPU is overheating or if your Power Supply or Memory (RAM)is on the way out, this can also cause your PC to slowdown.
I would start with the defrag and the disk cleanup using the windows maitenance tools, and then if this doesn't improve performance, you may then want to look into hardware possibilities.
I have no idea why but lately my computer has been going EXTREMELY slow. My computer is about a year old, and I Have 256mb of RAM. I haven't installed any new parts and haven't really changed anything, but the computer slows down nonetheless. I don't have any programs running in the background (that I shouldn't) and I'm not really running any major resource-draining programs. The only error I can think of that may be causing this is the fact that I cannot shut down my computer properly, it just hangs at the 'Windows is now shutting down' screen and I just cut the power at this point. I am running on WIndows 98SE. Thanks for any help.