Totally the wrong site for this kind of thing but basically run 'perfmon' from the Start menu, click on 'Data Collection Sets', right click on 'Used Defined', select 'New' and 'Data Collection Set'. Give it a name and select "Create Manually" then Next, tick "Performance counter" but leave the other two blank', select Next, click Add - from the next screen select 'Processor' and 'Total' from the two panels, then click Add>> then select OK, then Finish.
If you then right click on the new Data Collector Set set's name and select Start it'll start logging your CPU utilisation. Leave this running for however long you like, just select Stop in the same way to stop it.
Once you have this big log of your usage and have stopped it you can view it by clicking on the 'Performance Monitor' option at the top of that window, then either click on the 'View Log Data' icon (or press Control & L), click on 'Log Files', find the collector data log and select OK. Then click on the big green + plus icon and select the Processor and Total options again, then click the Add>> button and ok. This should then show you a bunch of data about your CPU/s during this time window - it's the '% Processor Time' you care about, you may need to deselect every other counter but that one and then right click on that counter selecting 'Scale Selected Counters' to see the graph properly.
If this proves that your machine is indeed busy then you can send a print-screen to your guy explaining the situation.