A laptop that has become slow is not one fault. At the SAI Laptop Service counter in Electronic City, pop-ups and locked files are treated by removing malware and cleaning the system. A slow or failing hard drive is a different job: it is replaced with an SSD or a new drive. Windows that needs a fresh install is a third job, done when the system will not boot or when you want a fresh start. The diagnosis decides which one you are looking at.
Faults that are not a slow system
A cracked, flickering, or black screen. A battery that swells or dies early. Keys that stick or stay dead after a spill. Loud fans, sudden shutdowns, and heat through the palm rest, traced to the fan and heat sink. The shop board also lists the motherboard and RAM, fitted when that part is the fault.
A slow machine is worth a call to 099724 47766 before you assume the drive is the fault. Ask for the quote before paid work. There is no price list on this site.
Start with the services page, then computer repair and Computer technician near me.