I can suggest some of the popular stores to buy electronics, including computers, in Los Angeles:
Best Buy - They have a wide range of electronics and computer-related products. They also provide technical support and installation services.
Fry's Electronics - It's a popular electronics retailer in California. They offer a wide range of electronics, including computer hardware and software.
Micro Center - It's a computer and electronics retailer that has a good selection of computer hardware, software, and accessories. They also provide technical support and repair services.
Apple Store - If you're looking for Apple products, the Apple Store in Los Angeles is a good option. They offer a range of Apple products, including Mac computers, iPads, and iPhones.
Amazon Books - Amazon has recently opened brick and mortar stores in LA, which offer a range of products including computers and electronics.
It's always a good idea to compare prices and reviews of the products you're interested in, and also consider factors such as warranties, return policies, and customer service before making a purchase decision