Slow Running XP initially

Hi

Not sure if this is the correct forum, apologies if its not, not sure if its a windows or hardware issue.
I have an XP pro system, with windows installed on an 80Gb PATA HDD. It has 1Gb Memory, and the MOBO is an ASUS A8V-E SE. The system ran Ok until it recently started to run slowly, when booting into windows. I never used to see the screen that says windows is starting up, which now persists for 5-10seconds before the login screen ( fast user switching enabled). And when I select an account it takes longer to boot into windows, and the HDD light is constantly flashing. In all takes around 3-4mins from when clicking the user account to PC being useable. All this seemed to happen after installing a 250Gb SATA drive as a backup for video editing. Windows appears to see this drive OK, as a SCSI drive, and the BIOS is set to use the drive in IDE mode rather then RAID. Boot sequence for the HDDs is set to use the PATA drive first. Should I install some other drivers??? I have run virus scans and 3 spyware scans ( spybot, Adaware, and counter spy) all find nothing amiss, so I beleive its something to do with the SATA drive as this is the only change I have made. After the first 3-5 mins the system is back up to speed with no slowness problems at all.

Any help would be appreciated.