A computer being slow can have a lot of possible causes. Some are hardware, some are software. The most common ones are simple poor maintenance, which means dirty, dusty hardware and cluttered, old, unused files on the hard drive.
On the hardware side, go to Walmart and buy a can of compressed air (make sure it still has the little red straw), and use that to clean out the heatsinks inside your computer (google your particular model if it's a laptop to see how to access it and do this). A vacuum can be used to help control the dust while you're doing this, just be careful with it.
Then you can use a utility to clean out your files, unclutter your registry, and then defragment your hard drive. I really, really like Piriform's products for this: CCleaner and Defraggler. They're both "freemium" – free basic versions with premium paid versions available – and perfectly safe to download and use (link below).
There are no websites that do that
Are you referring to an old computer or a new computer?
Are you referring to XP, Windows 7, Windows 8 or Windows 10?
Are you referring to boot up speed, general operating speed, or internet speed?
Are you referring to a pirate copy of Windows or legal copy?
All of the above are very important in helping diagnose slow speeds
1. If you have a pirate copy of Windows, that explains a lot of issues
2. If you have a legal copy of Windows, you need to make sure all of your windows updates are installed. These help, in part, fix software bugs that cause issues
3. You need to make sure your anti-virus and anti-malware are up to date. Run them to check for infection. This is the #1 thing that slows down computers
4. If your computer is old, you may have a hard drive that is starting to lose life
5. what do you have in start up? Delete unnecessary programs
6. run diskcleanup
7. run defrag
8. run the assessment tool on your computer. If it's less than 3 you might be due a new computer
9. get rid of unnecessary junk programs on your computer
10. Run your anti-virus and anti-malware
1 – 10 above will help with slow boot up and slow general operation
If you are referring to internet speed (upload, download, surfing) the only thing that will speed that up is get a new internet service package from your ISP that is faster
I know of not one website I could recommend as 100% safe. Download and install this little free http://www.piriform.com/ccleaner program that will do a great job of cleaning your computer. It can also be used to uninstall unwanted programs. Do not change any of the default settings and leave it as is. Run the cleaner first and then run the Registry Cleaner. It is perfectly safe as I have used it for over 10 years. Use it to uninstall programs instead of Windows Add/Remove as it does a much more through job. Once you run it then go back to your computer and start removing all videos, photos, and songs you do not need. This will free up hard drive space and help you PC to be a little taster. If you have less than 4 GB of ram then add as much ram as it can use.
There are none, they are all scams, mostly they set up masses of cache in RAM to make it seem faster. Between the lack of RAM for other use and the load of running the program it actually becomes slower. You need to first scan for malware, then turn off any startup programs you do not absolutely need. Uninistall all Internet optimisers, search assistants and similar as they are often wasting resources communicating with the Internet for nothing. Then use the ccleaner registry cleaner from http://piriform.com to clean the registry. Repeatedly scan until there are no more errors.
As far as I'm concerned there are none.Why pay for a service when you can do it your self for free. Install these free programs: MalwarebytesAnti-malware,CCleaner and AuslogicsDiskDefrag. Open Malwarebytes and run a complete scan for spyware and the like. After that open CCleaner,run the hard drive cleaner then do the registry. Then open Auslogics and defrag your hard drive.
which is the 'safest'