Computer and laptop repair businesses diagnose and resolve faults affecting desktop computers, laptops and related equipment. They may investigate devices that will not start, run slowly, overheat, crash or have problems connecting to the internet or peripherals. Repairs can involve replacing or repairing components such as screens, keyboards, batteries, power supplies, fans, memory and storage drives, depending on the device and the fault. Services may also include operating system installation or recovery, software troubleshooting, virus and malware removal, data transfer, file recovery and advice on backing up information. Some businesses carry out upgrades, such as adding memory or fitting a solid-state drive, and may set up printers, routers or other accessories. Work can be provided at a workshop, at a customer's premises or through a collection and delivery service.