Maybe DMA is not enabled. I recall something that it is Disabled by default.

So go to you devicemanager, select the Primary and Secondary IDE controller and there must some DMA selection possibilities. must be enabled on both the Controllers and both the devices connected to the Controller.

What PC are you running this on?

Windows 98 does not like to multitask. If this is on a 486, I'm gonna guess that's normal behavior. Don't listen to me though, I've never run 98 on a 486.

Sounds like DMA alright. Go to the Control Panel, open up System, go to the Device Manager from there. Then, find your HDD and Optical Drive and enable DMA on them. Restart and you should be good to go! 😀

I agree with the earlier posters. Also make sure Windows doesn't have to run in compatibility mode.
Some real-mode drivers could be causing trouble on your machine (see config.sys, also check autoexec.bat for mscdex).
And if you're running Windows on flash media, try other cards. Some behave jerky, because they weren't meant for small writes and/or multi-tasking.
Correct alignment may also be important for newer drives.

Thanks for all the troubleshooting information, sadly the problem with my system was when the promise sata tx2plus was connected it seamed to do something to the system, as soon i removed it the os start working with out problems.

I did dual boot from ide and from the card with sata disk and still had issues in os whenever it was ide or sata, removed the sata and the ide worked fine, even the ssd worked fine when using ide2sata converter. so i think my system dont like the promise card even whit lates firmware, sad since i didnt want to use a converter 😉