Hi Mylene,
Welcome to the Forum.
If Windows 10 ISO was downloaded to install it on your computer by the guy you used, its probably still got the downloaded files from that on your system. These are typically hidden folders on the
C:\ directory.
If you open File Explorer and navigate your way to
This PC > Local Disk C then in File Explorers ribbon at top
select View tab and
check the
Hidden items box my guess is you'll see folders appear like
$BT_
If that is the case you can use
Disk Cleanup to safely remove these files.
- Press Windows key + S together to give focus to the Search field
- In the search field type Disk Cleanup then press Enter key
- A small window will open with C drive selected -- click OK
- When that opens the larger winder click the Cleanup System files button which will take a few seconds to generate a new dialog. My guess is you'll see the 22 GB in the optimization folder, or possible another which is for windows recovery console.
You can choose to select and delete this, but it will warn you to confirm deletion as doing so means you cannot roll back to a previous build, nor use these files for general corrupt file repairs.
That means you'd need to download the 22GB again should this become necessary. So its your call as to whether you allow 22 GB to be taken up on your Disk, or whether you are prepared to download 22 GB at some later time which for many users would get close to their monthly data cap limits depending on their internet service provider plan.
By the way: If that 22 GB is in fact what I am suggesting it probably is, then it will not be the reason your system is running slower. If it turns out to be cached files for your Browser and Search indexes etcetera that might cause some slowness, and caches can be deleted safely but this means the index will need to be rebuilt or webpages you have save passwords on will need you to re-enter these to gain access to.