sistray could be the Prova Trojan. -> http://vil.nai.com/vil/content/v_99623.htm

Khooker:
http://www.answersthatwork.com/:
SiS Keyboard Daemon. System Tray utility which gets installed by the drivers of the latter day SiS VGA cards. The utility itself is not of much use in our opinion and may occasionally be contributing to Windows startup problems, although we have not been able to establish this for certain.
pctspk.exe
http://www.answersthatwork.com/:
Used for modems based upon PC-TEL chipsets. Normally used for some Voice and Speakerphone functions and also for some Power management options. If you remove it you may not be able to use any of those functions
tfswctrl:
Background task for Hewlett-Packard’s DLA software (Drive Letter Assignment). HP’s DLA gets installed when you installed the software that comes with their CD/DVD Writers. HP’s DLA is packet writing software which enables you to store data onto CD’s directly from within Windows applications, without using the actual CD Writing software (much like Roxio’s DirectCD.
thats a start at least...