If you are using Win XP, in Start/Run type chkdsk /r Enter. Then reboot the computer and let check disk scan your hard drive for problems.
Thank you ... will this take me into strange places like DOS or will it run a straight forward scan cheers
It runs before windows loads. Then opens windows. If you suspect problems with your HD you might want to do a fresh back up as chkdsk will segregate broken pieces of files, etc. Although the backup would be corrupt anyway.
It is possible you are starting to get hard drive problems when they are over 3 years old. Please note that no software can actually fix a failing hard drive. My suggestion is to back up all your important data, install a new hard drive, and do a clean reinstall of Windows and all your programs, then install anti-virus software and then copy back your data files. You should be able to back up your data files to a portable HD or a thumb drive if you don't have too much data. If you don't know how to do this, take it to a computer repair shop. Also, hard drives are pretty cheap now, so I would go with at least a 250 GB one. You can take out your old hard drive to determine what type to buy IDE or SCSI.
IF(big if) HD is falling apart(which does happens a lot on laptops mostly due poor ventilation) he should experience a lot of strange things way before this problem arise. again-check for errors, check for partitions\not formatted space. you can copy all your stuff on external HD(cost close to nothing) and consider to install SSD instead. but before that-you can clone\copy your current HD on external HD, delete,reformat old HD reinstall windows and put back all your stuff. it's should take 2-3 hours max