The .sta file extension is for Eudora Stationary so that isn't istbar.
Not clear about the software\microsoft\downloadmanager as being istbar either. On another machine running the same OS (WinME) this same key is identified as WindUpdates.
Performing conditional scans...
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istbar Object Recognized!
Type : Regkey
Data :
Category : Malware
Comment :
Rootkey : HKEY_CLASSES_ROOT
Object : .sta
istbar Object Recognized!
Type : RegValue
Data :
Category : Malware
Comment :
Rootkey : HKEY_CLASSES_ROOT
Object : .sta
Value :
istbar Object Recognized!
Type : Regkey
Data :
Category : Malware
Comment :
Rootkey : HKEY_LOCAL_MACHINE
Object : software\microsoft\downloadmanager