Fix Windows Stuttering Issue

My Windows PC stutters constantly, regardless of whether it's during startup, while running programs, or even while playing games. This issue started after I recently installed new hardware. I'm looking for an experienced technician who can diagnose and fix this problem... (Budget: £10 - £11 GBP, Jobs: Computer Repair, Computer Science, Network Administration, Performance Tuning, System Admin, Technical Support, Windows Desktop, Windows Server)