Actually Low disk space alert is a default in Windows XP. If u want to disable it then follow this:
There is a registry value you can set to disable this feature. To disable low disk space checks, follow these steps, log off, and then log on again: Follow these steps, and then quit Registry Editor:
1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following key in the registry:
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type NoLowDiskSpaceChecks, and then press ENTER.
5. On the Edit menu, click Modify.
6. Type 1, and then click OK
Now restart XP. And now u want to monitor cpu usage and memory consumption then U have to download Ramrush Portable software and it is totally free. The URL is: www.nonags.com/freeware-ramrush-portable_3708.html. Hope this works for u.
Windows XP SP3 or any late versions of Windows Operating System has its built in alert software for low disk space. When your computer runs low in storage space, it automatically alerts you for the problem. However, you can still use a third party alerting software for effectively monitoring your computer hardware activities.