Hi DinanSofian:
If you check the properties of this twunk_32.exe file (right-click on the file and choose Properties from the pop-up menu) is it published and/or digitally signed by a company called TWAIN or TWAIN Working Group? I don't have my Vista SP2 laptop with me today but most information I've found online indicates that the legitimate twunk_32.exe file is normally located in the C:\Windows folder (i.e., not C:\Windows\System32 or some other subfolder) and is part of the TWAIN Thunker software used to acquire images from web cameras, scanners, etc.
If you'd like to ensure your twunk_32.exe is not a malicious file, upload that .exe file to the VirusTotal.com site at https://www.virustotal.com/gui/home/upload for analysis. VirusTotal will calculate the SHA-256 hash (digital fingerprint) of the uploaded file and submit it to ~ 70 popular antivirus scan engines like Bitdefender, McAfee, Symantec, etc. for analysis. A score of 0/68, for example, would indicate that 0 of 68 scan engines found the file was suspicious / malicious and you could be confident the file was safe.
32-bit Vista Home Premium SP2 * Firefox ESR v52.9.0 * Norton Security v22.15.2.22 * Malwarebytes Free v3.5.1
HP Pavilion dv6835ca, Intel Core2Duo T5550 @ 1.83 GHz, 3 GB RAM, NVIDIA GeForce 8400M GS