Many older netbooks are underpowered (sub-par Atom processors in them and often they only have 1gb of RAM), however there are things you can do to help…
Firstly I’d bring up ‘msconfig’ to check what programs are working in the background when Windows has started up - most people only need their antivirus running - so uncheck any and everything else (stuff like itunes running can really slow some computer s down on startup and shutdown).
Then move on to doing a Disk Cleanup, followed by a Disk Defrag - this may take a while…
I’d then run ccleaner (free and easy to use program from filehippo.com), click on the ‘Registry’ option and then ‘Scan for issues’ followed by ‘Fix Issues’.
After that I’d move onto the obvious antivirus and Malwarebyes Antimalware scans - I’d recommend the Avast Free Antivirus if you think your current antivirus is doing a sloppy job or maybe slowing your pc down.
Probably be a good idea to download and run Rkill, Adwcleaner and TDSSKiller too - all free and effective programs from bleepingcomputer.com.
For Windows Updates I’d go for the automatic download but install them when you want option too 😃
If you’re using Google Chrome or a Chromium based browser go into the advanced settings and untick the ‘use hardware acceleration when available’ and ‘continue running background apps when closed’ - also have a look to ensure there are no extensions running that shouldn’t be, and your default search engine is what it should be.
Good luck with it - if your netbook has 2gb ram it may be noticably slower than it was a year ago - if possible check to see if the amount of RAM can be increased for your make and model (4gb+ would be great) - ebay do some good cheap memory.
Hope it helps 😃