If you think the card reader ma be suspect, try going into the BIOS and disabling it, if this cures the problem, you have saved the cost of a cable, however I have never known of a cable to run and fail, they normally either work or they do not.
As far as I know any modern IDE cable will work with any IDE drive (SATA cables are different)
You may be short of drive space on your hard drive,short of memory (Recommend 1gb for running XP), drives in need of defragging, or a trogan and / or a virus.
Are you running any USB devices that require power from your system, is you power supply 'Spike & Surge' protected.
Is the problem when ( e.g.) a kettle is switched on)
You may have to many programs running on your system (do a google for 'starter.exe', this will tell you what programs are running when you boot up your machine.
I hope this helps