Laptop Speakers Suddenly Gone All Scratchy, And System Is Sluggish And Lagging

[joko]

dell precision m6800. win 10

it just happened a couple of days ago, the drivers are up to date and cant see any errors in the device manager.

there are are no windows updates to install

it happens playing video etc but also system notification noises are distorted too.

the whole laptop has kind of gone sluggish too, cursor lags and it takes longer to do anything

virus scan is clean, does a clean up, defrag and chkdsk, with glary utilities, and 360 internet security

any ideas what this could be?

thanks

[Bertrum]

Have you checked to see if any processes running in the background are using a lot of resources?

[joko]

i did, andits saying 'very low' next to all of them except firefox which is moderate.

[joko]

its been like this for a few days and does it all the time, even when onlu just turned the machine on etc, when ive not opened any programmes. start up programmes are same as always and minimal

[fender62]

id backup your files external hard drive, and do a system restore.