I installed a soft ware which said its a antivirus software for pen drive?

it appeared to be like that

but wen i installed it it did not run any normal installation procedures

it opend a dos program then disappeared

but i had two diffrent files containing files which i never saw

it occupied about 250mbs of space in my pen drive

i was not able to format my pendrive in order to rectify that problem

so i used system restore option

with the pendrive still pluged inside

the system restored and i was able to format the pendrive

will those files still be in my system or will the problem continue

I installed a soft ware which said its a antivirus software for pen drive?hijackthis

As you restored your computer to an early time, it has freed up space on the pen drive, by removing those files. That means they no longer exist , neither on pen drive nor on your computer.