sounds like the drum hit overpowered/redlined the levels for that track and this caused the problem. Since it was working before this, this may have corrupted the program, or referencing the above post, this action might have 'muted' one of the master audio settings if the software for your program is a little unstable.
Close all programs and reboot the machine, if that doesn't uninstall/reinstall the recording program. Hopefully you have saved all your settings and recordings and tracks worth saving.
Also, 128 MB is on the low side. I would recommend doubling or tripling your RAM for audio recording, and of course, you don't want any other programs running while you are using the recording software.
Another thing that might help the overall performance is to define the virtual memory amouont instead of letting Windows expand and contract it as needed and as not needed. This causes alot more processing (that can be used for other functions), to take place. When you need more RAM, a portion of the hard drive acts like RAM.
If you define the amount of VM, than it sets the amount of hard drive space to a fixed amount. I have 312 MB of RAM on my 98 machine that I used to run Cakewalk on, and when I set my Virtual Memory min and max to 500, it fixed some performance issues I was having.
I'm gong to guess that you are using W98...........System Properties/Performance/Virtual Memory. (it will warn you that this action might make your system unstalble, but don't worry about that) You set the Min and Max to the same value, usually the standard is 1 1/2 timnes the amount of RAM installed, more or less. If you don't install more RAM as suggested, I would definitely define your virutal memory.
jam on, mon !