CPU Usage and Cdrw Drive

Just started getting a weird problem with a jump in CPU Usage to 20-25%.
It happens after using the Computer for awhile ( 1/2-1hr. ). The mouse
starts to drag and responses
to basic windows tasks become sluggish. I traced it to my cdrw drive. If I
disable it in
Device Manager the Cpu usage returns to normal. It doesnt happen with the
other drive
A Pioneer Dvd. My motherboard is archiac, EPox 8K3A + and is 5 yrs. + .
The LG cdrw
works fine reading and burning CD's.
Also, sometimes my choice of OS's get stuck at the boot.ini menu. If
I gently press on
the Computer Power On Button the OS starts to bootup.???