How can you tell if your Harddrive is working to spec?

Benchmark... more than likely, you've just collected a shit load of start up programs, or filled up a lot of space. Try running a registry cleaner, and delete anything unnecessary and you should be fine. Also watch out for trojans and viruses, like it even needs to be said.

What is a registry cleaner?

defrag, diskscan, debug, format, reinstall. Sounds like you're a prime candidate.

Ok just bought a registry cleaner, installed and ran

things pretty much same?

format c: and reinstall windows, no this is not a joke.

http://www.hddlife.com/ < rofl

http://www.tune-up.com/products/tuneup-utilities/ is a nice little utility and might help you out...But sometimes harddrives do just break so backup everything now.

I was serious about my previous post. If you haven't reinstalled in a long time (I usually do every 6 months to a year), you might want to consider it; you're computer will be a lot faster, assuming you don't put a bunch of useless programs back on it that load at startup.

Assuming you're running XP, I would:
(0) Backup everything
(1) DiskCheck the hard drive (ScanDisk on Win98)
(2) Defrag the hard drive
(3) Debug (this is a script run from a Win98 boot disk that will wipe your partitians...some viruses can't be destroyed by simply formating)
(4) Format from XP disk (will make you establish a partitian...choose NTSC)
(5) Reinstall Windows XP
(6) Reinstall your programs
(7) Check startup (both folder and msconfig.sys) to disable any unnecessary programs from starting up at boot
(8) Go through services to disable unnecessary services to improve performance and reduce security holes. If you need a list, hit me up and I'll send you one.

HDD Health v2.1 Build 159 Plus it's free. http://www.panterasoft.com/

It's just time for a reformat. After installing so much stuff over time the bootstrap becomes long winded.