some say a hard drive normally lasts 4 to 5 years so you could be nearing the end of its useful life. With an older system I limit things to possibly a bit more ram and a new hard drive. Working on the basis that if the system dies after a little while at least the new hard drive should be ok to move to a new system. The problem with that is the change from ide drives to sata. Probably your existing system only has provision for ide and newer systems have very little provision for ide drives being now mainly sata.