'taskmon.exe' is not a trojan, it is apart of the Windows Operating System. What makes you give out that advice which would lead me to delete it. I have 'Windows 98' and it may be rather useless but i've disabled it and will leave it on my system.
There may be a Trojan name similar to it or you are implying that even though it is a Windows file you class it as a Trojan.
Taskmon
The Windows Task Monitor. In theory the Task Monitor monitors your hard disks accesses. This information is then passed on to the Disk Defragmenter to supposedly enable it to defragment and rearrange the information on your hard disk in such a way that the programs and files you access the most, will load faster. First introduced in Windows 98.
Recommendation :
In rare cases Task Monitor has been shown to cause problems, so if you are troubleshooting a hard to find problem, disable it using Startup Manager – not only is it not a necessary item, but we also feel that on modern PCs the supposed benefits are negligible, if not totally unnoticeable.